If you're just trying to do projections for running the business at home you could calculate costs for utilities by looking at your annual costs (which you'll have) and then taking a percentage for the amount of time (and space) you'll be using for business.
An example of this is if it costs you £1,000 for heat (I'm using easy numbers!) and it's a 5 room house, then it's approximately £200 per year per room. If you will be using one room for business for 50% of the time, it will roughly be £100 per year to heat the room for business purposes. Does that make sense?
If you then want to use this cost to inform your price, you could divide the cost of your heating by your projected number of treatments per year.
So...... if you think you'll do 10 treatments per week, for 45 weeks of the year that's 450 treatments.
£100/450= £0.22
If you want to calculate the cost of one service (in order to be able to set your prices) then you need to use what's called a 'full cost recovery' approach. That means that you need to calculate every cost in to your price, this includes product, time, heat, light, product, uniform, insurance, equipment etc.
Your supplier should be able to provide you with a cost breakdown of a service.
Hope this helps